1. Field of the Disclosure
This invention relates to dental implants for anatomical restoration operations and surgeries. More specifically, this invention relates to dental implants with horizontal anchors and/or expandable root portions configured to improve mechanical retention. Additionally, this invention relates to a method of inserting a dental implant, and a bone structure that includes the dental implant.
2. Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present invention.
A dental implant is an artificial tooth root, typically of a cylindrical shape, which is placed into the jawbone to hold a replacement tooth or bridge. The placement of an implant requires creation of a site in the patient's jawbone for receiving the implant. The implant site is created by precision drills. The dental implant is then threadedly fitted or press-fitted in the implant site. However, the mechanical engagement between the bone and the dental implant at the time of insertion is generally inadequate to support an artificial tooth or prosthesis.
To alleviate this problem, a variable amount of time is allowed for the bone to grow around and into the implant, and thereby enhance the anchoring of the dental implant, which can then support an artificial tooth or bridge. This physiological process of the metal fusing with a living bone is called osseointegration.
Most dental implants are made of titanium or of a titanium alloy, due to the biocompatibility and high rate of osseointegration of titanium. Osseointegration typically takes 4 to 6 months. Any strain on or movement of the implant during this time can inhibit or prevent successful osseointegration. The time period required for osseointegration is uncomfortable for the patient due to its length, the requirement for multiple office visits, and the unpleasant cosmetic appearance.
Besides the need for osseointegration, the most basic dental implant technology has other shortcomings. As we age, the sinus cavity gets larger due to the natural loss of bone. This loss of bone results in reduced thickness in the upper jawbone, and complicates the implant process in that region. A minimum bone thickness of 1.5 millimeters is needed all around the implant to facilitate the implant process for a conventional implant support and anchorage. Additionally, the implant site should be a minimum of 1-2 millimeters away from any vital structure such as nerves. This might necessitate a bone graft procedure which can take an additional 6 to 9 months, adding to the total implant procedure time and of course increasing the overall cost.
Having a missing tooth for several months creates potential further problems such as shifting and chipping of adjacent teeth and problems with the temporomandibular joint (TMJ). TMJ is the area directly in front of the ear on either side of the head where the upper jaw (maxilla) and lower jaw (mandible) meet. The TMJ is used throughout the day to move the jaw, especially in biting and chewing, talking, and yawning. It is one of the most frequently used joints of the body. When a tooth is missing for an extended period of time, a patient might develop a new chewing habit in order to avoid the missing tooth. This can lead to a TMJ disorder.
Yet another potential problem is bone resorption. Bone resorption is the process by which osteoclasts break down bone and release the minerals, resulting in a transfer of calcium from bone fluid to the blood. Bone resorption is noticeable during the time required for osseointegration, due to the lack of pressure normally applied by the extracted tooth onto the bone tissue.
Expandable implants have been suggested and used to enhance the mechanical engagement between the dental implant and the jawbone, as in e.g., Flander (U.S. Pat. No. 3,708,883), Daftary et al. (U.S. Pat. No. 5,470,230) (hereinafter Daftary), Choung (U.S. Pat. No. 6,332,778), Lazarof (U.S. Pub. No. 2006/0194171), Vachtenberg (U.S. Pub. No. 2009/0208905), and Ghavidel (U.S. Pub. No. 2010/0304333); each of which is incorporated here by reference in its entirety such that the structural components and architectural features such as surface structures and attachment mechanisms described therein are a part of the present disclosure.
Generally, in expandable implants, the outer diameter of the implant relative to the wall of the site is adjustable. By providing a controlled amount of lateral expansion, the outer surface of the implant is in pressured, frictional engagement with the jawbone.
To provide more secure and stable mounting of the implant and allow the installation of the prosthesis and loading without the extensive waiting period, dental implants with additional support members or anchors may be used. Anchors also allow use of shorter implants which may eliminate the need for supplementary bone graft surgery. Several embodiments of anchors have been suggested in the prior art, as in e.g., Sapian (U.S. Pat. No. 5,890,902), Huang (U.S. Pat. No. 5,984,681), Laster et al. (U.S. Pat. No. 6,450,812) (hereinafter Laster), and Goldman (U.S. App. No. 2009/0004626); each of which is incorporated here by reference in its entirety such that the structural components and architectural features such as surface structures and attachment mechanisms described therein are a part of the present disclosure. In particular, Laster provides a detailed summary of several issues regarding dental implants, and a review of related technology.